The present invention refers to a method of using zeolites for adsorbing detergents. More specifically, it refers to the use of hydrophobic zeolites for adsorbing anionic, cationic and nonionic detergents in solutions containing such detergents.
Detergents, amphiphilic molecules containing a hydrophobic and a hydrophilic part, are commonly used chemicals within various techniques. The hydrophilic part of a particular detergent molecule can be either charged or uncharged and the detergents are thus characterized as anionic, cationic, or nonionic. In e.g. biochemistry, detergents are used mainly to stabilize emulsions, and solubilizing lipids, cell membranes, and protein aggregates.
Purification of membrane components and intracellular molecules is often carried out in the presence of detergents. However, of the common purification methods, ion exchange chromatography is interfered with by ionic detergents and an increased apparent molecular weight is obtained upon gel filtration in the presence of large micelles formed with nonionic detergents.
The development of cDNA technology and the increased production of recombinant proteins which are generated in the form of intracellular protein aggregates; "inclusion bodies", has increased the demand for both fast and large scale purification methods. To be able to freely chose among purification methods the detergent has to be removed after fulfilling its purpose, solubilization of proteins. Today this is achieved by dialysis, ion exchange chromatography, or absorption to hydrophobic matrixes. Dialysis is time consuming, especially if the detergent forms large micelles and has a low critical micelle concentration (CMC). Ion exchange chromatography of anionic and cationic detergents is thwarted by the net charge of the proteins. Adsorption of detergents to hydrophobic matrixes such as BioBeads SM-2 or Amberlite XAD-2 is effective. However, adsorption to the latter matrixes is not attainable with all kinds of detergents and large scale application of the method is expensive.
Thus there is a great demand for a fast and large scale purification method by means of which it is possible to efficiently remove all types of detergents.